[mutter/gbsneto/graphene2: 32/45] cogl/matrix: Apply perspective with Graphene

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit d0590de9e8a39b6bdab3fab59bc62ffa8b167cf4
Author: Georges Basile Stavracas Neto <georges stavracas gmail com>
Date:   Wed Feb 27 19:03:59 2019 -0300

    cogl/matrix: Apply perspective with Graphene

 cogl/cogl/cogl-matrix.c | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)
---
diff --git a/cogl/cogl/cogl-matrix.c b/cogl/cogl/cogl-matrix.c
index 7f0d3176c..97034ee7a 100644
--- a/cogl/cogl/cogl-matrix.c
+++ b/cogl/cogl/cogl-matrix.c
@@ -421,15 +421,16 @@ cogl_matrix_perspective (CoglMatrix *matrix,
                          float       z_near,
                          float       z_far)
 {
-  float ymax = z_near * tan (fov_y * G_PI / 360.0);
-
-  cogl_matrix_frustum (matrix,
-                       -ymax * aspect,  /* left */
-                       ymax * aspect,   /* right */
-                       -ymax,           /* bottom */
-                       ymax,            /* top */
-                       z_near,
-                       z_far);
+  graphene_matrix_t perspective, m;
+
+  graphene_matrix_init_perspective (&perspective, fov_y, aspect, z_near, z_far);
+
+  cogl_matrix_to_graphene_matrix (matrix, &m);
+  graphene_matrix_transpose (&m, &m);
+
+  graphene_matrix_multiply (&m, &perspective, &m);
+  graphene_matrix_to_cogl_matrix (&m, matrix);
+
   _COGL_MATRIX_DEBUG_PRINT (matrix);
 }